Aging is a condition in which a person gradually loses the ability to maintain homeostasis, due to structural alteration or dysfunction. Aging changes biological processes in many organs and tissues. The loss of regenerative capacity is the most dramatic age-associated alteration in the liver. Cellular damage, if not repaired, leads to apoptosis or senescence. The presence of permanent cell cycle arrest, the acquisition of major morphological change, and expression of senescence-associated β-galactosidase (SA-β-gal) are the characteristics of cellular senescence (CS). Interestingly, CS plays a crucial role in aging of both individual organs and the entire organism; consequently, senescent cells accumulate in organs and decline in organ function. Senescent cells have considerable influence on their microenvironment and exert both beneficial and detrimental effects through secretory associated senescent phenotype (SASP) factors. CS has attracted considerable recent interest with recognition of pathways linking aging, malignancy, and insulin resistance and the current focus on therapeutic interventions to extend healthspan. There are major implications for hepatology in the field of fibrosis and cancer, where cellular senescence of hepatocytes, cholangiocytes, stellate cells, and immune cells has been implicated in chronic liver disease progression.
Part of the book: Senescence